Automatic switch for telephone installations.



PATENTBD MAY 21. 1907.

P. HILIrEBRAN'D.. AUTUMATIG SWITCH POR TBLEPHQNE INsTALLAToNS.

AYLIUATION FILED AUGg 24., 1905.

2 sknzTsY-smm 1 PATENTED MAY 21, 19107.

'NoE 854,164.

P.HILDBBRAND. AUTOMATIC SWITGH POR TELEPHUNE INSTALLATIONS.

APPLIATIOI FILED AUG. 24. 1905.

2 SHEETS-SHEET 2.

PAUL HILDEBRAN D, OF MUNICH, GERMANY.

-UTOMATIC SWITCH FOR TELEPHONE INSTALLATIONS.

Specification-of Letters Patent. i

Patented May 21, 1907.

Application filed August 24, 1905. Serial No. 275,654.

To a/Z w/wm t may concern:

Be it knownthat L'PAUL HILDEBRAND, a subiect of the German Emperor, residing at Munich, Bavaria, German have invented certain new and useful mprovements in Automatic Switches for Telephone Installations, of which the following is a specification.

The present invention relates to an automatic switch for telephone installations allowing each subscriber with a single wire (transmitting and receiving wire) to become connected with any other desired subscriber of the system without callingup the exchange. This result is obtained by means of an aut matic switch disk for each subscriber located at the exchange by means of which the subscriber to be called is made acquainted with the number of the caller, the subscriber called then adjusting his switch to this number, whereupon the conversation can take place. y

The improvements are diagrammatically represented in the annexed drawing, Figure l showing the system, and Figs. 2 c 3, the dial and` switch disk mechanism, respectively.

Sheet 2 shows the construction of the subscribers switch-dial for moving the contactlever K on the switch-disk Sat the exchange. This mechanism consists of a toothed disk U capable of heilig rotated, whose teeth canse the contact device C to make contact, thereby exciting tln` magnet M of the switch-disk S, which magnet attracts a lever with pawl A and thus causes the contact-lever K to revolve, exactly in proportion to the revolution of the switch-disk U.

' llach switch at the exchange is provided with two zero or rest contacts or stops (Y) one for the transmitting wire and the other for the receiving wire and further lor each subscriber a series of contacts arranged in pairs, as shown in the drawing on thedifferent disks by the numerals 10, 10, 15, 15, 20, 2W. It will be seen from the dlagram that cach zero point otl a disk is connected by they wires ci cl" cli c2" rshown in dotted lines, to the call contacts ot 'the other disksl having thesame numbers ior example wire af to the contacts 5 on the disks S1" S15, S2" 'and so on or c1" to l() on S5, Sli', S2" and so on. ()n the other hand the speaking contacts having the index reference c are connected in pairs to each other by the uires 51" bm?, 1)5 shown in i'ull lines in such' a'manncr that lor example on the disk S5 the contacts ltrL are connected to the contacts 5a ol the disk S1 and the contacts 15 to the contacts 5 of the disk S, and so on.

A single switch dial is arranged at each instrument or speaking station said dials being provided with the same numbers as the switch disks in the exchange and arranged in such a manner that by adjusting or displacing a pointer from the zero point to the desired telephone number a similar number of current-impulsesis automatically produced in the known manner said impulses beingradapted to correspondingly adjust a contact lever K on the disk in the exchange station by means of an electro magnet and a suitable mechanism.

Theaction on making a call is as follows: If for instance subscriber 5 desires to be connected to subscriber 10, the former first adjusts the pointer of his contact dial from zere to the number 10, whereby at the exchange the contact lever of the disk S5 belonging to subscriber 5 is brought against the contacts 10. Since the contact lever on the disk S,

belonging to subscriber 1.0, is at zero, there is established the connection with the Pzero points of the disk S1" and with subscriber 10 by the contact arm of disk S1 by which an alarm bell is rungp foreach subscriber. The subscriber called first the number of the caller (in this case 5) and. by means ot the pointer on his dial brings the contact lever ol his disk S1" .at the exchange on the e contacts (speaking contacts) oi the caller (thus on In the meantime the caller by displacing the pointer of his dial from the point l() (call contact) to l0 (speaking contact) has brought the contact lever of his disk Syonto the 1contacts 1()nl and., as will be seenv from the draw-y ing the desired connection .of the disk to SU is produced., lna similar manner the subscribers`15 and 2() may also be connected,

'lhe special advantage of the improved szvitch resides in the fact that by the `arrangement'oi the a, contacts any interruption by a third party during the conversation is coni- 'pletely prevented since for the purpose olE calling the desired subscriber the contact lever l ol'l the latters disk at the exchange must be at zero.

ll" the wire is engaged the alarm hell does not ring on calling since the contact. lever on the callers disk at, the exchange is not at the zero point thus showing the caller that another connection exists.

'What Leiaim is:

in an automatic switch for telephonie in-l stailations with :L single transmitting and :receiving wire the e(,)'11'1binaton of a switch dial subtne speaking station and zi switch. disk et the exchange for euch subsciiber, s cimtziet lever on said disk zidap'tedfto. be opemined from said diei, :L zero or est Contact, a seiies of' cnil contacts and e series of speaking c011- tects for each speaking station on each of 4 said switch disks. and means for eiectrieeiy i?, esegesi 

